Aggregate behavior in amphiphilic coil/rod block copolymer solutions

Abstract

The self-assembly in coil/rod/coil BAB amphiphilic symmetric triblock copolymer solutions was investigated using lattice self-consistent field theory. At low concentrations, some peaks emerge on the heat capacity curve, i.e., multiple rearrangements (MRs) of micelles. For short hydrophobic rod blocks (HRBs), MRs are concerned with the emergences of vesicles, stellate, rod, and lamellar micelles (LMs), and the breakup and formation of LMs. At high concentrations with HRBs of intermediate length HRBs, MRs are associated to a few (quasi-)order/disorder transitions of micelles. For long HRBs, although only one quasi-order/disorder transition emerges, MRs do occur. It is found that the aggregation behavior of high concentrations with HRBs of intermediate length is similar to that of low concentrations compared with high concentrations with long HRBs. These results are explained by the reappearing behavior and dissolution, and the cooperative growth of micelles, where the micellar cores and coronas are rearranged alternately with temperature. This work is helpful for further interpreting the cooperativity and dynamics of self-assembly.